The influences of submerged vegetation Hydrilla verticillata on forms of inorganic and organic phosphorous forms and potentially exchangeable phosphate in sediments were investigated under indoors simulating condition. The results show that: (1) Hydrilla verticillata can decrease the amount of OM, CEC and TP evidently ( p < 0.05) and activate the phosphate in sediments. (2) In the forms of inorganic phosphorus, the NaOH-P was significantly influenced (p<0.01) and the labile organic P in the forms of organic P was influenced to a certainty (p < 0.1), while no significant differences were made to the other forms of phosphorous. (3) Hydrilla verticillata can affect the amount of potentially exchangeable phosphate of the sediments, which increased 11.5% for the vegetation-group and decreased 61.0% for the control group during the period of the experiments. The change orientation was oppositional and the degree of change was quite different. This testified that Hydrilla verticillata could increase the amount of potentially exchangeable phosphate of sediments.